Image result for windows with built-in security bars
GLASSESSENTIAL® Folding Window Grilles are designed to provide elegant look, strong security barrier with ease of operation.
Installing pin locks on double-hung windows is a good home security tip.
Security Window Film can Make Your Home More Secure
window slide panel | DIY Hurricane Window Protection - Plywood or Plastic Hurricane Panel ...
Decorative Window Bars - the next step. Just be sure they have a quick release, or you'll have to remove them when you sell. Fire code and all. :)
VIDEO: 3M Window Protection
Artsy window protections in Barcelona during Spanish Civil War c.1936
3M Window Protection - YouTube